Western Treatment Plant Explorer : Teacher Resources : Resource 23
Resource 23
Soil filtration ¹
Soil filtration setup.
Which are the best soils for filtering sewage?
You have to find out which is the better filter: a heavy soil with a lot of clay in it or a lighter soil with more sand.
Collect:
- 2 dishwashing liquid bottles with their bottoms cut off
- dirty water
- a sample of clay soil
- a sample of sandy soil
- 2 bosshead clamps
- 2 retort stands
- 2 beakers.
- Set up two sets of equipment as shown.
- Put some cotton wool into each of the containers to stop the soils falling through. Put 100 mm of clay soil into one of the upturned plastic bottles and 100 mm of sandy soil into the other.
- Fill the plastic bottles with dirty water and time how long it takes for 50 mL of water to filter through. Make a note of the appearance of the filtered water.
¹ Based on an activity from: Keith McTaggart and Paul Saddler 1993, Flushing Dunnies, Melbourne Water and Science Teachers Association of Victoria.